In the pulp industry, the wood used as raw material is cut into chips as required for the production process. Besides external dimensions, the chips must be of the right quality with respect to other properties as well. The chips are conveyed into a steaming silo and from there, they are further conveyed to the pulping process. In the silo, the moisture of the chips is adjusted to a suitable level by supplying steam into the silo. At the same time, the air among the chips, which is detrimental to the pulping process, is removed.
In previously known technology, the steam is supplied to different parts of the silo through steam supply pipes. To ensure that all parts of the silo receive enough steam, the steam supply points must be distributed in different parts of the silo walls and bottom. Therefore, the piping contains several branching points and is a complex structure. The steam is fed into the silo through perforated plates mounted on the pipe ends at the supply points. These perforated plates are blocked at times by chips accumulating on them or by impurities entering with the steam. This applies especially to the steam supply points in the bottom of the silo. The cleaning and possible replacement of the piping and perforated plates is a time-consuming operation which generally makes it necessary to empty the silo.